rocker arms

Discussion in 'PSI Superchargers Tech Questions' started by bill, Jan 8, 2015.

  1. bill

    bill Member

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    does everbody slaken there rocker arms for the winter when not in use
     
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  2. Mike Canter

    Mike Canter Top Dragster
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    Yes, and should release them between races
     
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  3. TD 4028

    TD 4028 Member

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    Yes, we do.
     
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  4. SoDak

    SoDak Active Member

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    I never had, I'm not saying its right but...


    What kind of ill effects can be happening if you don't back off the racker arms?
     
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  5. Mike Canter

    Mike Canter Top Dragster
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    You can loose tension on the valve springs.
     
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  6. Joad Donnelly

    Joad Donnelly Member

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    I don't claim to be a spring expert but I've never seen a spring (not just valve springs) weaken due to sitting in a compressed state that is within the design limits. I'll admit that I've never turned this into a science experiment (and I'm sure it's been done)and if I were to let my engine sit over the winter I would probably back them off as a feel good but I've never seen any evidence to back up this theory. I'm guessing springs weaken much more due to cycles and/or bouncing around out of control. I saw a guy back in high school attempt to lower his truck by strapping it down in a very compressed state and leaving it there for what ended up being close to a year and when the straps were released it hadn't changed the ride height at all.
     
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  7. Mike Canter

    Mike Canter Top Dragster
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    If you leave the rocker arms on then some of the valves are open with the springs compressed ant over a 1000 psi and some have valves closed at 400 psi and some are in between. I don't think truck springs equal that kind of force applied to them. Each to his own. I don't want a valve spring to fail.
     
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  8. Eric N/FC

    Eric N/FC Member

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    I totally agree with Mike.
    I suppose no one here leaves the parachutes packed during off-season? That pilot-chute spring does not like to be compressed in long periods of time because it can loose tension.
    I think it`s kindo the same thing.

    We even take off the heads just to un-stress the headstuds and threads in the block, dont know if that`s neccecary but we do it anyway.
    When I come to think about, we even take out the cranks to have them checked.
     
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    Last edited: Jan 9, 2015
  9. Joad Donnelly

    Joad Donnelly Member

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    The power of Google. lol I spent a minute poking around on the internet about springs and what I got out of it was for most part a springs decrease in strength is going to come from the cycles and not from sitting in a static compressed state. It sounds like there are a number of factors which come into play so there is probably not a totally "correct" answerer to this question for all springs. So I'm going with, if you want to play it safe don't store springs in a compressed state but most likely you're not going to noticeably weaken a spring by leaving it compressed. One example is the clicker type torque wrenches. I was always taught to back them off to zero after use because you would weaken the spring/screw up the calibration and I continue to do this. But I've seen plenty of people who don't due this and their torque wrenches pass calibration just as consistently as the ones which are always stored backed off.
     
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  10. Randy G.

    Randy G. Top Alcohol

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    Pull the pushrods...in fact pull the heads. You should be looking and checking everything anyway.
     
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  11. Mike Canter

    Mike Canter Top Dragster
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    At the aeronaudtical company I worked at they were really strick on how they handled torque wrenches. They had s strick calibration schedule because the springs inside changed value. The big problem is that our valve springs are really small for the pressures they are set at. Maybe a big spring set at 1000 psi can take it better than our small springs set at 1000 psi. There is no doubt that cycles Are the biggest factor in the life of a spring.
     
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  12. overkill69

    overkill69 Member

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    Springs

    I guess it comes down to where do you draw the line. We run over 500 psi on the seat which I consider to be a substantial load. Should we break down the valvesprings between races? We will tear our stuff down to nothing over the winter but I feel no sense of urgency to get the heads apart due to the load on the springs and valve stems. Compared to what the springs endure at 10000 rpm I would think sitting compressed in the shop is one of the easiest parts of their lives.
    We are a little more reluctant than some to tear our rocker gear off all the time because we run t&d with pressure oiling so when you take it apart you lose the prime and increase chances of a burned part.
    like Randy said, the stuff needs to be inspected anyway so usually we have the rockers off regardless of the spring compression.
     
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  13. TD 4028

    TD 4028 Member

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    I have always been told the springs would weaken if left compressed all winter, whether it does or not is really irrelevant in that it takes a whole 10 minutes to pull the rockers and 15-20 to put back on and line up.
    The other reason we pull them, is down here it gets stupid humid...even in the winter. and I want the holes all closed up. I pull the plugs, WD40 everything heavily and pull the rockers off and pushrods out if the heads are on. more so just to keep everything closed up and clean and dry...
     
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  14. aj481x

    aj481x Member

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    Here you go, we just took 8 used PAC hemi springs, tested them and took 8 long bolts with heavy washers and compressed 4 to their 400# height and 4 to 800#. Will open our time capsule in the spring and see what happens.
     
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  15. Joad Donnelly

    Joad Donnelly Member

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    Cool, I was thinking of doing the same thing! Let us know the results.
     
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  16. Joad Donnelly

    Joad Donnelly Member

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    This is in the aviation industry too. The way the torque wrenches are handled varied a lot depending on who's care they were in but they were all on a strict certification schedule. The calibration labs don't adjust/repair the wrenches if they're out, they just come back red tagged and are not allowed to be used unless they are repaired. It is very rare to have one come back as failed so that's why I say that the springs being left compressed doesn't seem to have much of an affect of the spring strength in this case because I know that many are stored in this state by some folks.
     
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  17. altered8

    altered8 Member

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    when I ran chevs we didn't bother backing off the rockers and never affected the springs, but a bigger worry for me with the hemi isn't spring pressure loss but initial start up without lubing the pushrods first.
     
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  18. go green

    go green New Member

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    I usually back off the rockers and take the pushrods out . You can rotate the engine over and no have to worry if the the pushrods flopping half on the adjuster and piling something up . I squirt WD-40 in the holes and lock it in for the winter break . I have had mice pack cat food in my headers even when it was on the car lift , those little bastards can get anywhere .The cat got a stiff talking to afterwards.
     
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  19. Ken Sitko

    Ken Sitko Super Comp

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    I would be more concerned about the rollers on the lifters flattening out, or the needle bearings inside being broken, or even the camshaft being deformed with all that load on it.
     
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  20. Eric N/FC

    Eric N/FC Member

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    Hey aj481x!

    I`m qurious! Have you opened the time capsule yet?:)
     
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